Normal Hearing Thresholds in Korean Adults Aged 20-79 Years: Establishing Reference Values and Comparison With...

This study aimed to establish age-specific and ear-specific normative hearing thresholds for Korean adults aged 20-79 years, examining interaural asymmetry, sex-related variations, internal consistency, and comparing findings with International Organization for Standardization (ISO) 7029:2017.

A total of 1,409 participants (382 men, 1,027 women) with otologically normal hearing were included in this multicenter cross-sectional study (2021-2024). Ear-specific audiometry was performed at standard frequencies (250-8000 Hz) with calibrated equipment across four hospitals in South Korea. Measurement equivalence across institutions was confirmed through equivalence testing.

Measurement equivalence was confirmed across institutions (± 4-dB equivalence bounds). Age-specific normative hearing thresholds were established for Korean adults. Significant interaural asymmetry was observed, with right ear thresholds higher than left ear thresholds by an average of 2.8 dB in women and 1.7 dB in men (p < .05), particularly in younger adults (20s-50s). Sex differences were significant at specific frequencies and age groups, with men demonstrating higher thresholds than women. Internal consistency varied significantly by sex and age group, with men showing lower consistency in middle-aged groups (40s-50s). Korean hearing thresholds diverged significantly from ISO 7029:2017 medians across most age groups and frequencies (elevations: 2.0-19.0 dB, p < .05). Minimum required sample sizes varied substantially across demographic subgroups.

This study provides age-specific and ear-specific normative hearing thresholds for Korean adults. The findings revealed statistically significant interaural differences and deviations from ISO standards, underscoring the importance of population-specific reference data and updating international standards with contemporary cohort-specific information.